1. Field
This disclosure relates generally to heat transfer units, like air conditioners and heat exchangers, and, more particularly, to heat transfer units used in hazardous environments.
2. Background
In industrial applications, it is not uncommon to have locations where cooling or heat transfer from a location or housing is needed, yet the ambient atmosphere in the area to which the heat will be transferred contains fine dust or flammable vapor or chemicals which, when subjected to high heat or localized arcing, become overly corrosive (such locations being individually and collectively referred to herein as “hazardous environments”). Such environments can pose a hazard because most conventional air conditioning or heat exchanger units contain components that have elements which should not be exposed to the hazardous environment, for example, motors, switches and relays, because they have the potential to create sparks or have one or more sufficiently hot surfaces that can interact with the dust or vapor to cause an explosion or ignition. Likewise, those sparks and/or hot surfaces can cause localized atmospheric chemicals to react with and quickly degrade components of the units themselves.
In an effort to address this problem, conventional heat transfer units that are used in such environments typically employ remedial approaches, such as relying upon use of explosion-proof hardware and enclosures, incorporating energy-limiting devices to reduce the possibility of arcing, or relocating spark-producing or high heat-producing components to locations well-removed from the hazardous environment. All such approaches however increase cost and complexity of the units.
Thus, there is a need for heat transfer units that can be used in hazardous locations but do not require such high cost and/or complex remedial efforts that have the effect of reducing reliability of their components relative to their normal counterpart components (e.g., non-explosion proof or energy-limiting).